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Appendix B Synthesizer Basics 478
Subtractive synthesizer components
The front panel of most subtractive synthesizers provides similar signal-generating and
processing modules—coupled with a number of modulation and control modules. The signal-
generating and processing modules typically run from left to right, mirroring the synthesizer’s
signal ow.
Output
ModulatorGlobal ctrl
AmplifierFilterOscillator
Input
Basic Synthesizer
Signal-generating and processing components
•
Oscillators: Generate the basic signal. This is usually a waveform that is rich in harmonics (see
Oscillators on page 479). Many synthesizers provide more than one oscillator, and almost all
synthesizer oscillators can generate several waveform types.
•
Filter section: Used to alter the basic signal by ltering out (removing) portions of the
frequency spectrum. Many synthesizers have a single lter that is applied universally to
all oscillator signals. Multioscillator synthesizers can provide multiple lters, allowing each
oscillator signal to be ltered in a dierent way (see Filters overview on page 482).
•
Amplier section: Used to control the level of the signal over time. The amplier has a module
known as an envelope, which is divided into several elements that provide level control for
the beginning, middle, and end portions of your sound. Simple synthesizers generally have
a single envelope, which is used to control the oscillator (and lter) over time. More complex
synthesizers can provide multiple envelopes (see Amplier envelope overview on page 485).
Modulation and control components
•
Modulators: Used to modulate the signal-generating and processing components. Modulations
can be machine-based—automatically generated by a synthesizer component—or can be
manually activated by using the modulation wheel, for example. Most synthesizers have a
component called an LFO (low frequency oscillator) to provide a waveform that modulates the
signal. See Modulation overview on page 487.
•
Global controls: Set the overall characteristics of your synthesizer sound, such as glides
between notes, pitch bends, and monophonic or polyphonic playback (see Global controls on
page 490).